Fire is one of the most common disasters that threaten the safety of the crowd in metro stations. Due to the variations in the design of metro stations, the hazard posed by the spreading products of the fire can pose different risks. The typical structures of metro stations in Guangzhou and Washington, D.C., are very different from each other. In Washington, D.C., the “high-dome” structure is predominant in the construction of metro stations, while in Guangzhou, most metro stations have the “flat ceiling” structure. In this article, a numerical modeling for fire dynamic simulation is used to predict and compare the spreading characters of fire products (the smoke height change, the temperature distribution and the visibility change) when fires with 2.5 MW heat release rate occur in the platform center and at the platform end in the two kinds of metro stations. The results show that, in the same fire scenario, the lowest smoke heights monitored in the Guangzhou model is 0.6 m (fire at the platform end) and 0.8 m (fire in the platform center) above the safe smoke height in 360 s after a fire breaks out, while it is 6.15 m (fire in the platform center) and 6.2 m (fire at the platform end) above the smoke height in the Washington model. The temperature increment in the Guangzhou model is 23 °C (fire in the platform center) to 29 °C (fire at the platform end) in 360 s after the fire breaks out, while the temperature increment in the same period in the Washington model is 8.5 °C (fire at the platform end) to 9 °C (fire in the platform center). The visibility of most areas on the platform of the Guangzhou model is about 1 m no matter the fire is in the platform center or at the platform end at 360 s after the fire begins, while in the Washington model, the visibility of most areas is 1.5–13.5 mm (fire at the platform end) to 4–14 m (fire in the platform center) at the same moment. Based on the results, the environment is worse when the fire happens at the end of the platform than that when the fire happens in the platform center of the Guangzhou model. While the fire location has fewer impacts on the smoke height, temperature, and visibility in the Washington model, metro stations with a high-dome structure can be beneficial to fire evacuation safety; however, the construction cost can be high. Metro stations with flat ceiling are widely used in more cities for it has lower construction cost; to compensate for its weaker abilities under fire conditions, it is suggested that smoke exhaust systems should be carefully and fully considered.

火灾是威胁地铁站人群安全的最常见灾害之一。由于地铁站设计的不同，火灾蔓延所造成的危害可能会带来不同的风险。广州和华盛顿特区地铁站的典型结构彼此大不相同。在华盛顿特区，地铁站建设以“高穹顶”结构为主，而在广州，大多数地铁站采用“平顶”结构。本文利用火灾动态模拟的数值模型对火灾发生时火灾产物的传播特性（烟高变化、温度分布和能见度变化）进行预测和比较。两种地铁站的站台中心和站台末端均出现5 MW的热释放率。结果表明，在相同火灾场景下，广州模型监测到的最低烟高在360 s后高于安全烟高0.6 m（平台端火灾）和0.8 m（平台中心火灾）。火灾发生时，它比华盛顿模型中的烟雾高度高 6.15 m（平台中心着火）和 6.2 m（平台端着火）。火灾发生后360 s内，广州模型的温升为23°C（平台中心着火）至29°C（平台端着火），而华盛顿模型的同期温升为是 8.5 °C（在平台末端着火）到 9 °C（在平台中心着火）。火灾发生后360 s，无论火灾发生在平台中心还是平台末端，广州模型平台上大部分区域的能见度均在1 m左右，而华盛顿模型中，大部分区域的能见度为同时从 1.5–13.5 mm（在平台端开火）到 4–14 m（在平台中心开火）。结果表明，火灾发生在广州模型的平台末端时的环境比发生在平台中心时的环境更差。虽然华盛顿模型中火灾位置对烟雾高度、温度和能见度的影响较小，但具有高圆顶结构的地铁站有利于消防疏散安全；然而，建设成本可能很高。平顶地铁站建设成本低，在更多城市得到广泛应用；为弥补其在火灾条件下较弱的能力，建议对排烟系统进行仔细和充分的考虑。